lungs, airways, oxygen exchange, pneumonia, bronchial asthma English: breathing


Breathing is needed to supply the body with oxygen. To do this, the body absorbs oxygen from the air via the lungs (pulmo) and releases it in used form as carbon dioxide (CO2). The regulation of breathing is subject to complex control mechanisms and is managed by many different muscle groups.

Respiratory chain

The respiratory chain is a vital process that takes place in the mitochondria. This is basically about energy production. So-called reduction equivalents (NADH+H+ and FADH2) are formed before the respiratory chain from components of our food, such as sugar, fat and protein.

These reduction equivalents are then used in the respiratory chain via various complexes to produce ATP (adenosine triphosphate). The respiratory chain consists of 5 complexes, which are located in the inner mitochondrial membrane. In simple terms, a proton gradient is built up over the first 4 complexes.

This means that many protons are located outside the membrane and thus an imbalance is created. To compensate this imbalance, the direction of flow is directed towards the inside of the membrane. The 5th complex of the respiratory chain takes advantage of this pressure and produces ATP with the help of the proton flow.

ATP is a universal energy supplier and is needed everywhere in our body (for example for muscle activity or chemical processes in cells). In total, 32 ATP can be produced from one sugar molecule, which can then be used. If the respiratory chain is no longer active, this has serious consequences. So-called cyanides, also known as prussic acid, inhibit the respiratory chain and thus prevent the formation of ATP. This leads to death within a short time.

Respiratory Musculature

The muscles that are responsible for the inflow and outflow of air from the lungs are called respiratory muscles. The most important respiratory muscle is the diaphragm. It is a quasi ring-shaped, flat muscle that forms the boundary between the chest and abdominal viscera and is attached to the edge of the body wall and the spinal column.

When the diaphragm is relaxed, the central part bulges hemispherically into the thorax, as there is less pressure here than in the abdomen. If the muscles are now tensed, the diaphragm lowers and becomes almost horizontal and even. This increases the volume in the thorax (ribcage) and thus in the lungs.

This means that the pressure in the lungs is lower than in the air. This negative pressure is the driving force for the air inflow (inhalation, inspiration). Depending on posture, parts of the intercostal muscles and individual muscles of the shoulder girdle can also support the inhalation (respiratory auxiliary muscles).